As semiconductor devices become highly integrated, a gap between adjacent metal lines decreases. Meanwhile, due to high dielectric constant (k) of an insulating material used for insulating adjacent metal lines, a capacitance between the adjacent metal lines increases and an RC delay occurs, leading to degradation of device characteristics.
As semiconductor devices are scaled down, interlayer dielectric (ILD) layers for isolating adjacent metal layers become thinner, which causes interference between a top metal layer and a bottom metal layer. In addition, when a dielectric constant of the ILD layer is high, a capacitor is naturally formed between the ILD layer and the top/bottom metal layers.
In recent years, studies have been conducted on novel materials and methods for manufacturing semiconductor devices using the same in order to reduce the dielectric constant of the ILD layer interposed between the metal layers.